35 + 65 + 75 + 25
= ???????????
55 x 55 =
75 x 65 =
25 x 25 =
35 x 35 =
55 x 55 =3025
75 x 65 =4875
25 x 25 =625
35 x 35 =1225
55 x 55 =3025
75 x 65 = 4875
25 x 25 =625
35 x 35 = 1225
tim cach tinh nhanh nhat cho cac cau hoi :
25*25
35*35
45*45
55*55
65*65
75*75
85*85
95*95
15h+45+25+35+65+75+85+95=?
15+45+25+35+65+75+85+95
=15+25+35+45+65+75+85+95
=(15+25+35+45)+(65+75+85+95)
=120 + 320
=440
tick nha Đức Dương
15+25+35+45+55+65+75+85+95=
15 + 25 + 35 + 45 + 55 + 65 + 75 + 85 + 95
= ( 15 + 85 ) + ( 25 + 75 ) + ( 35 + 65 ) + ( 45 + 55 ) + 95
= 100 + 100 + 100 + 100 + 95
= 495
Ngô Quang Ninh:
15 + 25 + 35 + 45 + 55 + 65 + 75 + 85 + 95
= (15 + 85) + (25 + 75) + (35 + 65) + (45 + 55) + 95
= 100 + 100 + 100 + 100 + 95
= 495
Tham khảo nha!
2 . 53 . 27 + 6 . 9 . 87 - 3 . 18 . 40 = ???
12 . 25 + 29 . 25 + 59 . 25 = ???
43 . 37 + 93 . 43 + 57 . 61 + 69 . 57 = ???
12 . 53 + 53 . 172 - 53 = ???
35 . 54 + 35 . 58 + 65 . 75 + 65 . 45 = ???
39 . 8 + 70 . 3 + 31 . 8 = ???
2 . 53 . 27 + 6 . 9 . 87 - 3 . 18 . 40
= 2. 53 . 9 . 3 + 2. 3 .9 .87 - 3 .2 .9 .40
= 54.53+54.87-54.40
=54(53+87-40)
=54. 100=5400
12 . 25 + 29 . 25 + 59 . 25
= 25 . ( 12+29+59)
=25 . 90
=2250
43 . 37 + 93 . 43 + 57 . 61 + 69 . 57
= 43.(37+93)+57(61+69)
=43.130+57.130
=130.(43+57)
=130.100
=13 000
12 . 53 + 53 . 172 - 53
=53(12+172-1)
=53.184
=9752
35 . 54 + 35 . 58 + 65 . 75 + 65 . 45
=35(54+58)+65(75+45)
=35.112+65.120
=3920+7800
=11720
39 . 8 + 70 . 3 + 31 . 8
=8(39+31)+70.3
=8.70+70.3
=70.(8+3)
=70.11
=770
2 . 53 . 27 + 6 . 9 . 87 - 3 . 18 . 40
= ( 2 . 27 ) . 53 + ( 6 . 9 ) . 87 - ( 3 . 18 ) . 40
= 54 . 53 + 54 . 87 - 54 . 40
= 54(53+87-40)
= 5400
12 . 25 + 29 . 25 + 59 . 25
= 25( 12 + 29 + 59 )
= 2500
43 . 37 + 93 . 43 + 57 . 61 + 69 . 57
= 43( 37 + 93 ) + 57(61 + 69 )
= 5590 + 7410
= 13000
12 . 53 + 53 . 172 - 53
= 53( 12 + 172 ) - 53
= 9752 - 53
= 9699
35 . 54 + 35 . 58 + 65 . 75 + 65 . 45
= 35( 54 + 58 ) + 65( 75 + 45 )
= 3920 + 7800
= 11720
Tính nhanh:15+25+35+45+55+65+75+85
15 + 25 + 35 + 45 + 55 + 65 + 75 + 85
= (15 + 85) + (25 + 75) + (35 + 65) + (45 + 55)
= 100 + 100 + 100 + 100
= 400
15+25+35+45+55+65+75+85
=(15+85)+(25+75)+(35+65)+(45+55)
=100+100+100+100
=400
15+25+35+45+55+65+75+85
= ( 15+85) +( 25+75)+ ( 35+65)+( 45+55)
= 100+100+100+100=4 x 100 = 400
nhanh nhé
5+15+25+35+45+55+65+75+85+95=?????????
= ( 5 + 95 ) + ( 15 + 85 ) + ( 25 + 75 ) + ( 35 + 65 ) + ( 45 + 55 )
= 100 + 100 + 100 + 100 + 100
= 5 x 100
= 500
a, 35 x 34 + 35 x 38 + 65 x 75 + 45 x 65
b, 39 x 8 + 60 x 2 + 21 x 8
c, 58 x 75 + 58 x 50 - 58 + 25
d, 125 x 98 - 125 x 46 - 52 x 25
a.35 x 34 + 35 x 38 + 65 x 75 + 45 x 65
= 35 x (34 + 38) + 65 x 75 + 65 x 45
= 35 x 72 + 65 x (75+45)
= 35 x 72 + 65 x 120
= 35 x 72 + 65 x (72 + 48)
= 35 x 72 + 65 x 72 + 65 x 48
= (35+65) x 72 + 65 x 48
= 100 x 72 + 65 x 48
= 7200 + 3120
= 10320
b.39 x 8 + 60 x 2 + 21 x 8
=39 x 8 + 15 x 4 x 2 +21 x 8
= 39 x 8 + 15 x 8 + 21 x 8
=(39 + 15 + 21) x 8
= 75 x 8
= 600
c.58 x 75 + 58 x 50 - 58 + 25
= 58 x 75 + 58 x 50 - 58 x 1 + 25
= 58 x(75+50-1)+25
= 58 x 124 + 25
= 7192 + 25
= 7217
d.125 x 98 - 125 x 46 - 52 x 25
= 25 x 5 x 98 - 25 x 5 x 46 - 25 x 52
= 25 x 490 - 25 x 230 - 25 x 52
= 25 x (490 - 230 - 52)
= 25 x 208
= 5200
tính hợp lí : 15+20+25+30+35+40+45+50+55+60+65+70+75
(15+75)+(20+70)+(25+65)+(30+60)+(35+55)+(40+50)+45
= 90+90+90+90+90+90+45
= 90.6+45
= 540+45=585
Số số hạng là:
(75-15):5+1=13(số)
Tổng là:
45x13=585